Apparatus for migrating virtual machines to another physical server, and method thereof

ABSTRACT

An apparatus obtains response information including a result of processing executed by a virtual machine operates on the first device, calculates the first value that is used to evaluate a response time from transmission of the request information to reception of the response information, calculates a ratio of processing capability of the first device to processing capability of the second device, calculates, based on the first value and the ratio, a second value that is used to evaluate a processing time until a response for a request is received when the virtual machine operates on the second device, determines the second device to be a migration destination candidate of the virtual machine when the second value is smaller than a threshold value, migrates the virtual machine that operates on the first device to the migration destination candidate to turn off the power of the first device.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2012-287748, filed on Dec. 28,2012, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a technology to control an informationprocessing system.

BACKGROUND

In recent years, a virtualization technology by which a plurality ofvirtual machines (VM) is operated on a single server at the same timehas been prevailed. By using the virtualization technology, an operatingsystem (OS) can be operated in each of the VMs. Therefore, a pluralityof OS can be operated in parallel on the single server, and a serverresource can be utilized effectively.

In addition, there has been a need for effective use of resources of acomputer system that includes a plurality of physical servers. As such atechnology by which the resources of the computer system are usedeffectively, for example, there are the following technologies.

As a first technology, there is a technology by which resources areautomatically reallocated on the basis of a measurement result based ona service level target correspondingly to various types of applications.In the first technology, a table of resources that include a server, anetwork, and a storage, an application table that indicatesconfiguration elements of an application that operates on theseresources, and a table of allocation of the resources to the applicationare held. A performance measurement item template that is used togenerate a measurement item of performance information from these piecesof configuration information, a performance measurement unit thatmeasures the measurement item of the performance information using aperformance measurement engine, and a resource allocation change rulethat is used for reallocating resources from the configurationinformation are generated. The reallocation of resources is performed inaccordance with the generated resource allocation change rule andconfiguration information.

As a second technology, there is a technology by which remigration of avirtual server is reduced. In the second technology, the virtual serveris connected to a plurality of physical servers on which the virtualservers can be operated, and a virtual server migration control devicethat migrates the virtual server that operates in any of the pluralityof physical servers to another physical server executes the followingprocessing. The virtual server migration control device detects loads onthe plurality of physical servers and calculates a time period duringwhich a load smaller than a predefined low load determination thresholdvalue is detected, for each of the physical servers. The virtual servermigration control device identifies a migration destination physicalserver that is a migration destination of the virtual server from amongthe plurality of physical servers using the calculated time period, andcauses the virtual server to be migrated to the identified migrationdestination physical server.

In a third technology, in a computer system in which a plurality ofservers are connected to each other through a network and one or morebusinesses are running, a power reduction mechanism of a managementserver migrates the business under a certain condition to reduce powerthat is consumed by the computer system.

In a fourth technology, deployment server candidates are selecteddepending on failure possibility of a spare server in a dynamicdeployment time period, a deployment server candidate that can satisfyrequirements of deployment to a system is selected from the deploymentserver candidates and is determined to be a deployment server.Therefore, for a required time period, a server is dynamically deployedto a system the performance of which is insufficient.

Patent literature 1: Japanese Patent Laid-Open No. 2005-174201

Patent literature 2: Japanese Patent Laid-Open No. 2009-116380

Patent literature 3: Japanese Patent Laid-Open No. 2011-90704

Patent literature 4: International Publication No. WO 2008/041302

SUMMARY

According to apparatus for controlling an information processing system,the apparatus includes a memory and a control unit. The control unit isconfigured to perform a process including: obtaining responseinformation that includes a result of processing executed by a virtualmachine that operates on a first information processing device, inresponse to request information that is transmitted to the informationprocessing system that includes a plurality of information processingdevices, the first information processing device being included in theplurality of information processing devices; calculating a firstevaluation value that is used to evaluate a response time fromtransmission of the request information to reception of the responseinformation; calculating a ratio of processing capability of the firstinformation processing device to processing capability of a secondinformation processing device, the second information processing devicebeing included in the plurality of information processing devices;calculating, based on the first evaluation value and the ratio, a secondevaluation value that is used to evaluate a processing time fromtransmission of the request information to reception of the responseinformation when the virtual machine operates on the second informationprocessing device; determining the second information processing deviceto be a migration destination candidate of the virtual machine when thecalculated second evaluation value is smaller than a first thresholdvalue; and migrating the virtual machine that operates on the firstinformation processing device to the migration destination candidate toturn off power of the first information processing device.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an information processing system control device in anembodiment.

FIG. 2 illustrates a configuration example of a server management systemin the embodiment.

FIG. 3 illustrates an example of physical server management informationin the embodiment.

FIG. 4 illustrates an example of virtual server management informationin the embodiment.

FIG. 5 illustrates an example of service management information in theembodiment.

FIG. 6 illustrates an example of a safety level table in the embodiment.

FIG. 7 illustrates an example of operation information of a virtualserver in the embodiment.

FIG. 8 illustrates an example of an entire processing flow of the servermanagement system in the embodiment.

FIG. 9 illustrates an example of a flow of selection processing (S12) ofa business service to be migrated in the embodiment.

FIG. 10 illustrates a data structure example of an appearance rateinformation (Y00-1) analysis table or an appearance rate information(Y00-2) analysis table in the embodiment.

FIG. 11 illustrates an example of a time zone candidate table in theembodiment.

FIG. 12 illustrates an example of a flow of first exclusion processingin a case where there is no power consumption effect (exceptionprocessing depending on an aggregation time interval) (S13) in theembodiment.

FIG. 13 is a diagram illustrating reading-out of record groups [j],[j+1], . . . , and [j+Y] of consecutive hours from the appearance rateinformation (Y00-2) analysis table in the embodiment.

FIG. 14 illustrates an example of a flow of exclusion processing in thecase where there is no power consumption effect (scheme in whichfrequent migration is prevented from a viewpoint of power consumption)(S14) in the embodiment.

FIGS. 15A-15C illustrate an example of a flow of selection processing(S15) of a virtual server to be migrated and a physical server that is amigration destination in the embodiment.

FIG. 16 illustrates an example of a migration availability server listin the embodiment.

FIG. 17 illustrates an example of a flow of exclusion processing in thecase where there is no power consumption effect (availabilityverification of a physical server candidate that is a migrationdestination) (S16) in the embodiment.

FIGS. 18A and 18B illustrates an example of an incident management tablein the embodiment.

FIG. 19 illustrates an example of a migration enable time periodcalendar in the embodiment.

FIG. 20 illustrates an example of a server operation schedule calendarin the embodiment.

FIGS. 21A and 21B illustrate an example of a flow of processing ofmigration of a virtual server and power-off processing of a physicalserver (S17) in the embodiment.

FIG. 22 is a diagram illustrating processing of S17-7 to S17-9.

FIG. 23 illustrates an example of a migration/power-off candidate tablein the embodiment.

FIG. 24 illustrates an output example of a power consumption reductionamount after migration in the embodiment.

FIG. 25 is a configuration block diagram of a hardware environment of acomputer to which the embodiment is applied.

DESCRIPTION OF EMBODIMENTS

Users of a data center, however, request performance target (servicelevel) for each business service, but in the above-described technology,reduction in power consumption of the information processing systembased on the service level is not considered.

As an aspect of the present invention, there is provided a technologyfor reducing power consumption of the information processing systemwhile the service level is taken into consideration.

As described above, efficient utilization of resources of a computersystem has being required. For example, as the efficient utilization ofresources of the computer system, an energy-efficient large-scale datacenter that is represented by a cloud has being required. Thelarge-scale data center performs collective management in cloudcomputing by which collective management of hardware, software, data,and the like is performed, as a new utilization form of information andcommunication technology (ICT) system construction.

The power consumption in the data center is mainly classified into twotypes: (i) power of an air conditioning facility to reduce heat that iscaused by hardware, and (ii) usage power of hardware (server, networkdevice, and the like).

As reduction measures of (i) power of the air conditioning facility, itis conceivable that the data center is installed in a cold region.

As reduction measures of (ii) usage power of the hardware, it isconceivable that, in a service that operates in a plurality of physicalservers, the number of operating physical servers is reduced byvirtualization and integration of a server and the usage power isreduced. The server virtualization integration refers to an operation ofa plurality of virtual servers on, for example, a single physicalserver. By operating a system, which has been operated in a plurality ofphysical servers by that time, in a single physical server, the numberof servers can be physically reduced.

In the above-described server virtualization integration, the number ofoperating physical servers is further reduced by migrating the virtualserver to another physical server using a performance measurement valuein a unit of virtual server without departing from a range of theperformance target value of the virtual server. As the performancemeasurement value, for example, there is the following IT equipmentutilization (ITEU) as an index that indicates that how much processingcapability of a device that is introduced to the data center is actuallyused.ITEU=total measured power of an IT device/total rated power of the ITdevice.

In the server virtualization integration, it is required that thefollowing matters are considered. There are many cases where a businessservice (may be simply referred to as service) is provided by aplurality of servers such as a WEB server, an application (APL) server,a database (BD) server. Here, the business service refers to providing aresult that is processed by a front server, the DB server, a back-endserver, and the like when there is a request from the user to a businesssystem, and refers to a series of pieces of processing until theprovision of the result or a server that executes the series of piecesof processing.

There is a difference in the usage frequency (load) of the businessservice depending on a time zone. In addition, the performance target(service level) that is required by the user of the data centercorresponds to a unit of the business service.

Therefore, in order to suppress excessive power consumption of the datacenter while the demand of the user of the data center is satisfied, itis required that the virtual server is migrated in the unit of businessservice, and the number of operating physical servers is reduced.

In the embodiment, in order to suppress the excessive power consumptionof the data center while the demand of the user of the data center issatisfied, the virtual server is migrated in the unit of businessservice, and the number of operating physical servers is reduced. As anexample in which the service level is increased and extra power isconsumed, the following cases are considered.

-   -   The usage is concentrated in the daytime, and the usage        frequency is low in the night time, in a time zone of one day.    -   The usage is concentrated in the weekday, and the usage        frequency is low in the weekend.    -   The usage is concentrated at the end of a period, and the usage        frequency is low during the period.

Hereinafter, a time zone having a high service level is determined fromthe service level state of the business service (tendency in a short,medium, long term). In addition, without departing from a range of aservice level agreement (SLA) value, a physical server on which thevirtual server is operated is changed, and the number of operatingphysical servers (physical servers the powers of which are turned on) isreduced.

FIG. 1 illustrates an information processing system control device in anembodiment. An information processing system control device 1 includesan obtaining unit 2, a determination unit 3, and a control unit 4. As anexample of the information processing system control device, there is amanagement server 11.

The obtaining unit 2 obtains response information that includes a resultof processing executed by a virtual machine 8 that operates in a firstinformation processing device 7-1 among a plurality of informationprocessing devices 7, in response to request information that istransmitted to an information processing system 6 that is constituted bythe plurality of information processing devices 7. As an example of theobtaining unit 2, there is a collection unit 22.

The determination unit 3 calculates a first evaluation value that isused to evaluate a response time from transmission of the requestinformation to reception of the response information. The determinationunit 3 calculates a ratio of processing capability of the firstinformation processing device 7-1 to processing capability of a secondinformation processing device 7-2 among the plurality of informationprocessing devices. The determination unit 3 uses the first evaluationvalue and the ratio to calculate a second evaluation value that is usedto evaluate a processing time from transmission of the requestinformation to reception of the response information when the virtualmachine 8 operates in the second information processing device. Thedetermination unit 3 determines the second information processing device7-2 to be a migration destination candidate of the virtual machine 8when the calculated second evaluation value is smaller than a firstthreshold value. In addition, the determination unit 3 determines thesecond information processing device 7-2 to be the migration destinationcandidate of the virtual machine when a value of a usage rate of aresource of the second information processing device 7-2 is smaller thana second threshold value. As an example of the determination unit 3,there is a candidate determination unit 24.

The control unit 4 migrates the virtual machine 8 that operates in thefirst information processing device 7-1 to the migration destinationcandidate and turns off power of the first information processing device7-1. The control unit 4 determines the migration destination candidatefor each of the plurality of information processing devices when aplurality of virtual machines operates in the first informationprocessing device 7-1 and the response information is processed by allor a part of the virtual machines among the plurality of virtualmachines. The control unit 4 migrates all or a part of the virtualmachines that perform the processing on the migration destinationcandidate when the first information processing device 7-1 is notdetermined to be the migration destination candidate. Examples of thecontrol unit 4 include a VM migration control unit 26 and a power-offcontrol unit 27.

By the above-described configuration, the migration of the virtualserver is performed in the unit of business service, so that the powerof the server that is a migration source is turned off and the number ofoperating physical servers can be reduced. Therefore, power consumptionof the information processing system can be suppressed while the safetylevel of the service is taken into consideration.

The control unit 4 calculates mean time between failures (MTBF) usingfailure history information of the second information processing device7-2. The control unit 4 obtains the most recent failure occurrence dayfrom the failure history information. The control unit 4 calculates anext failure occurrence predicted day from the failure occurrence dayand the MTBF. The control unit 4 migrates the virtual machine thatoperates in the first information processing device to the migrationdestination candidate in any day during a time period from the mostrecent failure occurrence day to the next failure occurrence predictedday, and turns off the power of the first information processing device.

By the above-described configuration, migration of the virtual machinecan be performed in a time period during which a probability thatfailure does not occur in the migration destination candidate is high.

The information processing system control device further includes anidentification unit 5. The identification unit 5 calculates anevaluation value that is used to evaluate processing performance fromtransmission of the request information to reception of the responseinformation. The identification unit 5 calculates an appearance rate ofan evaluation value for each of evaluation values in a first unit oftime. The identification unit 5 identifies a first time zone in whichany of the appearance rates exceeds a threshold value in the evaluationvalues. As an example of the identification unit 5, there is a serviceidentification unit 23.

By the above-described configuration, a time zone having a high servicelevel can be determined from the service level state (tendency in ashort, medium, or long term) of the business service.

In addition, the identification unit 5 calculates an appearance rate ofthe evaluation value for each of the evaluation values in a second unitof time, which is a lower-level of the first unit of time, andidentifies a second time zone in which any of the appearance ratesexceeds a threshold value in the evaluation values, out of consecutivetime zones in the second unit of time. An example of the identificationunit 5, there is an exception processing unit 25.

By the above-described configuration, an appearance rate of a safetylevel of a service that is biased depending on a time zone isconsidered, and the service can be identified.

In addition, the identification unit 5 excludes the identified firsttime zone when the identified first time zone includes a certain day ora certain time zone, and excludes the identified second time zone whenthe length of the identified second time zone is shorter than athreshold value. As an example of the identification unit 5, there isthe exception processing unit 25.

By the above-described configuration, power consumption due to frequentmigration can be prevented.

Hereinafter, the embodiment is described in detail.

FIG. 2 illustrates a configuration example of a server management systemin the embodiment. In the server management system, the managementserver 11 and a data center 17 (physical servers 12 (12 a, 12 b, and 12c)) are connected to each other through a certain communication network.The management server 11 is connected to an information processingterminal (hereinafter, referred to as “terminal”) 20 through a certainnetwork such as the Internet or a local area network (LAN). Anadministrator uses the terminal 20 to input service level information ofconfiguration information that is included in the business system and acertain parameter.

The physical server 12 functions as plurality of virtual servers(virtual machine: VM) by executing a virtual machine monitor (VMM) as avirtualization program.

In the data center 17, the physical servers 12 are connected to eachother through a certain network. The physical server 12 includeshardware, a VMM, and a plurality of virtual servers 13. The hardwarecorresponds to a physical device group that includes a real CPU (centralprocessing unit) and a real storage device. The hardware is describedlater. The VMM corresponds to a program that is used to provide avirtual hardware environment for the virtual server 13 in order tocontrol so as to operate the plurality of virtual servers 13 in thephysical server 12. Specifically, the VMM performs dispatch of an OS ofeach of the virtual servers 13 (control right allocation of physicalCPUs), emulation of privileged instruction that is executed by each ofthe OSs, and control of the hardware such as the physical CPU.

Each of the virtual servers 13 corresponds to a virtual computer thatoperates on the VMM independently of another virtual server 13. Each ofthe virtual servers 13 is achieved when each of the OSs obtains controlright of the physical CPU that is hardware through the VMM and isexecuted on the CPU.

For example, in the physical server 12 a, virtual servers such as frontservers 13 a and 13 b, a back-end server 13 c operate. In the physicalserver 12 b, virtual servers such as front servers 13 d and 13 e, aback-end server 13 f operate. In the physical server 12 c, a virtualserver such as a DB server 13 g operates. In such an example, the frontserver corresponds to a WEB server, but not limited to the WEB server.In such an example, the back-end server corresponds to an APL server,but not limited to the APL server.

In addition, the physical servers 12 a, 12 b, and 12 c respectivelyinclude transmission units 16 a, 16 b, and 16 c. The transmission units16 a, 16 b, and 16 c respectively transmit pieces of operationinformation of the physical servers 12 a, 12 b, and 12 c, or pieces ofoperation information of virtual servers that operate in the physicalservers 12 a, 12 b, and 12 c to the management server 11.

The management server 11 includes the obtaining unit 21, the collectionunit 22, the service identification unit 23, the candidate determinationunit 24, the exception processing unit 25, the VM migration control unit26, the power-off control unit 27, an output unit 28, and a storage unit29. The obtaining unit 21 obtains information that is input by theadministrator from the terminal 20.

The collection unit 22 obtains operation information of the physicalserver or the virtual server, which is transmitted by the transmissionunits 16 a, 16 b, and 16 c.

The service identification unit 23 analyzes the operation informationthat is obtained by the collection unit 22 and identifies a candidate ofa service to be migrated.

The candidate determination unit 24 determines a candidate of a virtualserver that can be migrated and a candidate of a physical server thatcan be a migration destination on the basis of the operation informationof the physical server and the virtual server related to the identifiedservice and the information that is obtained from the terminal 20.

The VM migration control unit 26 determines whether or not a physicalserver on which the virtual server that can be migrated is operated canbe turned off, and migrates the virtual server to the physical serverthat is a migration destination when the power-off is possible. Thepower-off control unit 27 transmits a command to turn off the power ofthe physical server that is a migration source, to the physical server.

The output unit 28 outputs information on a power consumption reductionamount of the whole system after the virtual server has been migrated,to an output device such as a display device and a printer.

The storage unit 29 is a device that includes a storage function such asa transitory storage device or a large capacity storage device. In thestorage unit 29, a work table, system configuration information,information that is obtained from the terminal 20, and operationinformation that is obtained by the collection unit 22 are stored. Thesystem configuration information includes physical server managementinformation that is used to manage specification or the like of aphysical server, virtual server management information that is used tomanage a virtual server that operates on a physical server, and servicemanagement information that is used to manage a service.

FIG. 3 is an example of physical server management information in theembodiment. Physical server management information 30 is stored in thestorage unit 29. The physical server management information 30 includesdata items of “physical server name”, “number of clocks”, “CPU usagerate”, “memory usage rate”, and “busy rate of a disk”. In “physicalserver name”, a name that identifies a physical server is stored. In“number of clocks”, the number of clocks of a processor that isinstalled in the physical server is stored. In “CPU usage rate”, a usagerate of the processor is stored. In “memory usage rate”, a usage rate ofa memory that is installed in the physical server is stored. In “busyrate of a disk”, a busy rate of a hard disk or the like that isinstalled in the physical server is stored.

FIG. 4 illustrates an example of virtual server management informationin the embodiment. Virtual server management information 40 is stored inthe storage unit 29. The virtual server management information 40includes data items of “physical server name” and “virtual server name”.In “physical server name”, a name that identifies a physical server isstored. In “virtual server name”, one or more names each of whichidentifies a virtual server that operates on the physical server arestored.

FIG. 5 illustrates an example of service management information in theembodiment. Service management information 50 is stored in the storageunit 29. The service management information 50 includes data items of“service name”, “virtual server name”, and “average online responsetime”. In “service name”, a name that identifies a service is stored. In“virtual server name”, a name that identifies a virtual server thatperforms the service is stored. In “average online response time”, anaverage online response time from request for the service to response tothe request is stored.

FIG. 6 illustrates an example of a safety level table in the embodiment.A safety level table 55 is a table that manages a SLA value of abusiness service, and is stored in the storage unit 29. The safety leveltable 55 is a table that indicates a relationship between a safety leveland a ratio of an online response time to SLA. When the safety level is1, a ratio of an online response time to SLA corresponds to 0% to 20%.When the safety level is 2, a ratio of an online response time to SLAcorresponds to 20% to 40%. When the safety level is 3, a ratio of anonline response time to SLA corresponds to 40% to 60%. When the safetylevel is 4, a ratio of an online response time to SLA corresponds to 60%to 80%. When the safety level is 5, a ratio of an online response timeto SLA corresponds to 80% to 100%.

FIG. 7 illustrates an example of operation information of a virtualserver in the embodiment. Operation information 56 of a virtual serverincludes pieces of information A01 to A19. The management server 11obtains the operation information 56 of a virtual server from thevirtual server to analyze the virtual server to be migrated, and storesthe operation information 56 in the storage unit 29. Information A01corresponds to a time at which a request is input to a front server.Information A02 corresponds to a time at which the request is outputfrom the front server (to a back-end server). Information A03corresponds to a time at which the request is input to the back-endserver. Information A04 corresponds to a time at which the request isoutput from the back-end server (to a DB server). Information A05corresponds to a time at which the request is input to the DB server.Information A06 corresponds to a time at which a response is output fromthe DB server (to the back-end server). Information A07 corresponds to atime at which the response comes into the back-end server. InformationA08 corresponds to a time at which the response is output from theback-end server (to the front server). Information A09 corresponds to atime at which the response is input to the front server (from theback-end server). Information A10 corresponds to a time at which theresponse is output from the front server. Information A11 corresponds toa CPU usage rate of the front server. Information A12 corresponds to amemory usage amount of the front server. Information A13 corresponds toan input/output (I/O) busy rate of a disk of the front server.Information A14 corresponds to a CPU usage rate of the back-end server.Information A15 corresponds to a memory usage amount of the back-endserver. Information A16 corresponds to an I/O busy rate of a disk of theback-end server. Information A17 corresponds to a CPU usage rate of theDB server. Information A18 corresponds to a memory usage amount of theDB server. Information A19 corresponds to an I/O busy rate of a disk ofthe DB server.

FIG. 8 illustrates an example of the entire processing flow of theserver management system in the embodiment. When the administrator usesthe terminal 20 to input information related to a business service tothe management server 11 (S11), the management server 11 stores theinput information in the storage unit 29. The information related to thebusiness service includes, the physical server management information30, the virtual server management information 40, the service managementinformation 50, a SLA value of the business service, a basic value thatis used to migrate a server (migration time interval, safety levelvalue, and the like).

The management server 11 executes processing of selecting a businessservice to be migrated (S12). The management server 11 obtains basicinformation of the business service and operation information of thebusiness service from a physical server that includes a virtual serverto analyze the business service to be migrated. The basic information ofthe business service corresponds to system configuration information andservice level information. The system configuration informationcorresponds to information on a configuration of a physical server andinformation on a configuration of a virtual server that operates on thephysical server. The operation information of the business serviceincludes information on an average online response time of the businessservice.

The management server 11 obtains “time at which a request is input tothe front server (for example, Web server)” and “time at which aresponse is output from the front server” from the physical server 12,as the operation information of the business service. The managementserver 11 aggregates/analyzes the obtained operation information in“unit of hour”, “unit of day”, “unit of month”, or “unit of quarter”.

After that, the management server 11 classifies a service level value(=online response time/average online response time×100%) into safetylevels (for example, five stages) and selects a business servicecandidate to be migrated on the basis of the safety level.

Here, the management server 11 classifies a service level value (onlineresponse time) into the safety levels (five stages). As an index that isused to measure safety of the service level, for example, safety levelsthat are segmented into the five stages are defined.

Safety level 1: The safety is high, and there is sufficient processingcapability.

Safety level 2: The safety is high, and there is some sufficientprocessing capability.

Safety level 3: The safety is high, but there is no sufficientprocessing capability.

Safety level 4: The safety is slightly low.

Safety level 5: The safety is low.

In addition, the management server 11 selects a migration servicecandidate from the operation information that is aggregated/analyzed onthe basis of the safety level. The management server 11 selects aservice in which an appearance rate of a safety level n is m % or morefrom the data that is obtained by performing aggregation in a unit ofaggregation (hour/day/month/quarter). That is, the management server 11analyzes the specified safety level and the appearance rate in thecertain unit of time, and detects a service having a high safety leveland the time zone.

After that, the management server 11 excludes a first case where thereis no power consumption effect, from the selected business services(S13). Here, the management server 11 executes processing in whichexception due to a difference in an aggregation time interval isconsidered. In the migration service candidate that is selected in S12,there is a case where inconsistency occurs in the detection result dueto the difference in an aggregation time interval such as day, month, orthe like.

For example, it is assumed that, in a case of data that is obtained byperforming aggregation in the unit of “month”, when a day in which thesafety level n for each day exceeds m % is detected, there is a casewhere only a certain time zone of a certain day is different from theresult that is obtained by performing aggregation in the unit of day. Inthis case, the detected candidate may be wrong. Therefore, themanagement server 11 also performs analysis in a unit of aggregation,which is a lower level of the adopted unit of aggregation, and correctsthe detection result as exception of the unit of aggregation during atime in which a time zone of the lower level elapses for a certain time.

After that, the management server 11 excludes a second case where thereis no power consumption effect, from the selected business services(S14). Here, the management server 11 executes processing of preventingfrequent server migration from a viewpoint of power consumption. Thatis, there is a case where migration in the unit of one hour or a timezone at the peak time of power consumption is determined as a candidate,as the aggregation time candidate that is selected in S12. There is acase where, in the migration in the unit of one hour, an intended powerconsumption reduction is not obtained when the migration time isconsidered. A migration enable minimum time interval is set beforehandby considering such a case, and the migration within time range iseliminated from the candidate.

In addition, the management server 11 executes processing of selecting avirtual server to be migrated and a physical server candidate that is amigration destination for the selected business service (S15). Themanagement server 11 obtains the operation information 56 of the virtualserver, which is used to analyze the virtual server to be migrated, fromthe physical server 12.

The management server 11 calculates processing performance informationof each of the virtual servers in response to a request for the service(online response time, a processing time of each of the virtual servers,an occupation proportion of the processing time of each of virtualservers in an online response time) from the obtained operationinformation 56 of the obtained virtual server.

The management server 11 selects a virtual server candidate that is amigration target and a physical server candidate that is a migrationdestination. Here, the management server 11 detects the physical servercandidate that is a migration destination of the virtual server on thebasis of a safety level of the service after migration and a processingcapability of the physical server that is a migration destination.

The management server 11 excludes a third case where there is no powerconsumption effect, from the selected physical server candidates thatare migration destinations (S16). Here, the management server 11verifies availability of the migration destination physical servercandidate. The management server 11 verifies server migration from aviewpoint of the availability for the migration destination physicalserver that is detected as a candidate in S15. The above-describedprocessing is performed in order to prevent deterioration of a servicelevel of the availability with the server migration beforehand.

First, the management server 11 calculates MTBF of the physical serverthat is a migration destination candidate from the operation result.Here, in the storage device of the management server 11, a failurehistory of the physical server is recorded as incident data, so that themanagement server 11 calculates MTBF of the physical server using theincident data. In addition, the management server 11 may calculate MTBFby adding MTBF of a physical server the type of which is the same asthat of the physical server to the calculated MTBF.

After that, the management server 11 verifies the availability of themigration candidate. Here, the management server 11 compares a migrationcandidate time zone with the MTBF of the physical server, and excludesdays (times) before and after a next failure occurrence predicted day(time) when the next failure occurrence predicted day (time) is includedin the migration candidate time zone.

In addition, the management server 11 performs migration so as to copythe virtual server to the physical server that is a migrationdestination, and turns off the power of the physical server that has nooperating virtual server on the basis of the migration result (S17).Here, the management server 11 determines whether or not the power of aphysical server on which the virtual server that is a migration targetis operated can be turned off, on the basis of a certain condition. Thecondition is that all virtual machines of the physical server areenabled to be migrated to another physical server, and that the physicalserver is not selected as a candidate of a migration destination serverof the virtual machines.

In addition, the management server 11 performs migration of the virtualserver and turns off the power of the physical server. Here, themanagement server 11 builds the virtual server that is a migrationtarget on the physical server that is a migration destination by theserver migration before a migration enable time. The management server11 switches the physical server on which the virtual server that is amigration target is operated from the migration source physical serverto the migration destination physical server at the migration enabletime. The management server 11 turns off the power of the physicalserver that is a migration source.

The management server 11 calculates a difference in power consumptionamounts before and after migration, and outputs information on a powerconsumption reduction amount after migration (S18). In S18, informationon “operational consumption power of the physical server (at the time ofa system usage rate 0%)”, “operational consumption power of the servicebefore migration in a migration time zone”, “operational consumptionpower of the service after migration in the migration time zone”, and“reduction enable consumption power due to migration” is used.

The management server 11 calculates operational consumption power of theservice by combining operational consumption power of all operatingphysical servers on which the systems used for the service are operated.In addition, the management server 11 calculates consumption power thatis reduced by migration by calculating a difference between “operationalconsumption power of the service before migration in the migration timezone” and “operational consumption power of the service after migrationin the migration time zone”.

The management server 11 outputs the following information, for example,in a certain format such as a comma separated values (CSV) file, as apower consumption reduction amount.

-   -   Business service name of a migration target    -   Time zone of the migration target    -   System configuration before migration (physical server name and        virtual server name)    -   Operational consumption power before migration    -   System configuration after migration (physical server name and        virtual server name)    -   Operational consumption power after migration    -   Consumption power that is reduced by migration

FIG. 9 illustrates an example of a flow of the selection processing(S12) of a business service to be migrated in the embodiment. Themanagement server 11 obtains information required for analysis, andcalculates appearance rates (Y00) of the safety levels 1 to 5 in theunit of time (S12-1). In the basic information required for analysis,the information that is input in S11 and stored in the storage device 29and operation information of the business service are included. Theinformation that is stored in the storage device 29 includes informationon an average online response time of the business service. Theoperation information of the business service includes “time at which arequest is input to the front server (for example, Web server)” and“time at which a response is output from the front server”.

The management server 11 calculates an online response time from adifference between “time at which a request is input to the front server(for example, Web server)” and “time at which a response is output fromthe front server”. The management server 11 calculates a ratio of theonline response time to SLA on the basis of “(calculated online responsetime)/(“average online response time” of the service managementinformation 50)×100”.

The management server 11 classifies the calculated ratio of the onlineresponse time to SLA into the safety levels 1 to 5 using therelationship table in FIG. 6. The relationship table in FIG. 6 is storedin the storage unit 29. The management server 11 aggregates theclassified safety levels in “unit of hour”, “unit of day”, “unit ofmonth”, or “unit of quarter”. Hereinafter, aggregation of the safetylevels 1 to 5 in the certain unit of time by calculating a ratio of theonline response time to SLA from the pieces of information A01 to A19and classifying the calculated proportion into the safety levels 1 to 5may be referred to as “aggregation of the operation information of thebusiness service”.

The management server 11 calculates an appearance rate of each of theaggregated safety levels in a unit of minimum “time” (may be referred toas analysis of the operation information of the business service). Here,the appearance rate of a safety level corresponds to a proportion of thenumber of appearance times of a safety level n in the total number oftimes by which the safety levels 1 to 5 appear in the unit of time. Forexample, it is assumed that the following safety levels appear duringone hour of 14:00 to 15:00 in a certain day.

Safety level 1: three times

Safety level 2: two times

Safety level 3: zero times

Safety level 4: eight times

Safety level 5: two times

Total number of times of the safety levels 1 to 5: 15 times

In this case, an appearance rate of each of the safety levels is asfollows.

Safety level 1: 3/15=20%

Safety level 2: 2/15≅13%

Safety level 3: 0/15=0%

Safety level 4: 8/15≅53%

Safety level 5: 2/15≅13%

In addition, an appearance rate of a safety level of the service in theunit of day/month/quarter is calculated by the following method. Here,the appearance rate in the unit of day/month/quarter corresponds to anaverage value of appearance rates in a unit that is a lower level of thetarget unit. For example, in the case of the 4th of a certain month inthe unit of day, an appearance rate of a safety level n of the 4th ofthe month corresponds to an average value of appearance rates of thesafety level n in the unit of time that is a lower-level of the 4th ofthe month (=(total average value)/24 hours).

However, in a case where an average value of appearance rates of thesafety level is obtained, for example, when an appearance rate of thesafety level 1 corresponds to 100% in most of a time during 10:00 to16:00 (day time) of the 4th of the month, and the other time correspondsto 0%, an average value of the appearance rates of the safety level 1 isas follows.The average value of the appearance rates of the safety level1=(100%+100%+100%+100%+100%+100%)/24 hours=25%At that time, in a case where it is assumed that an appearance rate of acondition of a selection target is 80%, although 100% of the appearancerate of the safety level 1 continues in the day time of the 4th of themonth, but the service is not treated as the selection target. Asdescribed above, when there is a large gap between appearance rates inone day, the service is determined as a correction target in exceptionprocessing (S13) that is described later.

After that, the administrator uses the terminal 20 to input inputinformation such as an adopted unit of aggregation (Y01), an adoptedappearance rate (Y02), an adopted safety level (Y03), an adoptedduration time (Y04), a switching unnecessary time (Y05), and a minimumswitching interval (Y06), to the management server 11 (S12-2).

The adopted unit of aggregation (Y01) corresponds to information on aunit of time (day/month/quarter) that is adopted when aggregation andanalysis of the operation information of the business service areperformed. In the aggregation/analysis of the operation information ofthe business service in the unit of time, adopted of the unit of day,unit of month, unit of year, or unit of half period is differentdepending on the nature of the business service. For example, “unit ofday” is input for a business in which routine work is performed everyday. In addition, “unit of month” is input for a business in which abusy period is different depending on weekday or holiday. In addition,“unit of year” is input for a business in which a busy period isdifferent depending on month.

The adopted appearance rate (Y02) corresponds to a value (%) of anappearance rate that is adopted when aggregation and analysis of theoperation information of the business service are performed.

The adopted safety level (Y03) corresponds to a value of the safetylevel (integer of 1 to 5) that is adopted when aggregation and analysisof the operation information of the business service are performed.

A service level value at the time of aggregation is arbitrary ensured bythree values of the adopted unit of aggregation (Y01), the adoptedappearance rate (Y02), and the adopted safety level (Y03). For example,when “adopted unit of aggregation: day”, “adopted appearance rate: 80%”,and “adopted safety level: 1” are satisfied, the service of theoperation information of the appearance rate 80% or more of the safetylevel 1 on which aggregation/analysis is performed in the unit of day isdetermined as a selection target (*1).

The adopted duration time (Y04) corresponds to information that is usedto determine the operation information that is not treated as theselection target as a correction target in the exception processing asdescribed above, and to the adopted duration time (Y04), a time in whichan operation time of a physical server or a virtual server elapses(duration time) is set. The adopted duration time (Y04) is used tocorrect a target that is not treated as an aggregation target when thereis a large gap of appearance rates of the safety level in one day. Forexample, when “adopted duration time: four hours” is satisfied, theaverage value of appearance rates of the safety level 1 in 4th of themonth is 25% in the above-described example, so that the service isoutside of the selection target in the above-described condition (*1).However, when the adopted duration time (Y04) is used, the appearancerate of the safety level 1 is 80% or more for consecutive four hours ormore, so that the service can be selected.

The switching unnecessary time (Y05) is used to specify a time in whichthe aggregation/analysis cannot be performed because theaggregation/analysis just cannot be performed in a target time due tothe nature of the business even when a candidate time of a selectiontarget is determined.

The minimum switching interval (Y06) is specified when theaggregation/analysis is performed in a case where there is a time of theminimum switching interval or more. For example, there is a case wherethe aggregation/analysis or the like every one hour becomes wastedaggregation from a viewpoint of power consumption. Therefore, theaggregation/analysis is performed using the minimum switching interval(Y06) when there is the time of the minimum switching interval or more.The minimum switching interval (Y06) is used for the exceptionprocessing in S13.

After that, the management server 11 obtains “appearance rateinformation (Y00-1)” in the unit of time that corresponds to “adoptedunit of aggregation (Y01)” and “appearance rate information (Y00-2)” inthe unit of lower-level time, out of the appearance rates of the safetylevel of the service on which the aggregation/analysis has beenperformed in S12-1. The management server 11 stores “appearance rateinformation (Y00-1)” in an appearance rate information (Y00-1) analysistable, and stores “appearance rate information (Y00-2)” in an appearancerate information (Y00-2) analysis table (S12-3). The appearance rateinformation (Y00-1) analysis table and the appearance rate information(Y00-2) analysis table are described using FIG. 10.

FIG. 10 illustrates a data structure example of the appearance rateinformation (Y00-1) analysis table or the appearance rate information(Y00-2) analysis table in the embodiment. An appearance rate information(Y00-1) analysis table 60 and an appearance rate information (Y00-2)analysis table 70 are stored in the storage unit 29. Each of theappearance rate information (Y00-1) analysis table 60 and the appearancerate information (Y00-2) analysis table 70 is a work table that includesdata items of “hour (day, month, or the like)”, “service name”, “safetylevel”, “appearance rate”. In “hour (day, month, or the like)”, “hour”,“day”, “month”, or the like that corresponds to the adopted unit ofaggregation is stored. In “service name”, a service name is stored. In“safety level”, a safety level of the service that corresponds to “hour(day, month, or the like)” is stored. In “appearance rate”, anappearance rate of “safety level” that corresponds to “hour (day, month,or the like)” is stored.

Returning to FIG. 9, the management server 11 reads out a record groupfrom the appearance rate information (Y00-1) analysis table in the unitof hour (day, month, or the like). For example, in FIG. 11, five records(safety levels 1 to 5) in a time zone of “14:00 to 14:59” are read outas one record group (S12-4).

The management server 11 determines whether or not there is a record theappearance rate of which exceeds n % (=“adopted appearance rate (Y02)”)under a determination condition that the safety level is y (=“adoptedsafety level (Y03)”) in the read-out record group (S12-5).

When there is the record that satisfies the determination condition(“Yes” in S12-6), as illustrated in FIG. 11, the management server 11stores a service name and a time zone that are included in the record inthe time zone candidate table (S12-7).

FIG. 11 illustrates an example of a time zone candidate table in theembodiment. A time zone candidate table 80 includes data items of“service name” and “time zone candidate”. In “service name”, the name ofa service, which is used to identify a service is stored. In “time zonecandidate”, a candidate of a time zone that corresponds to the serviceis stored.

The management server 11 repeats the processing of S12-4 to S12-7 by Ttimes (S12-8). Here, “T” is a value that depends on the adopted unit ofaggregation, and for example, when the adopted unit of aggregationcorresponds to “year”, “T=12” is obtained, and when the adopted unit ofaggregation corresponds to “month”, “T=28 (29), 30, or 31” is obtained,and when the adopted unit of aggregation corresponds to “day”, “T=24” isobtained.

As described above, by creating a time zone candidate table of thebusiness service, the business service is selected as a migrationcandidate.

After that, the exclusion processing of the first case where there is nopower consumption effect (S13) is described with reference to FIGS. 12to 14.

FIG. 12 illustrates an example of a flow of the exclusion processing ofthe first case where there is no power consumption effect (exceptionprocessing depending on an aggregation time interval) in the embodiment(S13). FIG. 13 is a diagram illustrating reading-out of record groups[j], [j+1], . . . , and [j+Y] of consecutive hours, from the appearancerate information (Y00-2) analysis table in the embodiment.

In the flow, the management server 11 analyzes whether or not there is atime zone in which an operating state of the physical server or thevirtual server elapses for Y hours (=adopted duration time (Y04) ormore) for the appearance rate information (Y00-2) analysis table 70.

First, the management server 11 initializes a counter variable j by 1(S13-1). As illustrated in FIG. 13, the management server 11 reads outthe record groups [j], [j+1], . . . , and [j+Y] of consecutive hours(days, months, or the like) from the appearance rate information (Y00-2)analysis table 70 (S13-2).

The management server 11 determines whether or not there is a record theappearance rate of which exceeds n % (=“adopted appearance rate (Y02)”)under the determination condition that the safety level is y (=“adoptedsafety level (Y03)”) in the read-out record groups ([j], [j+1], . . . ,and [j+Y]) (S13-3).

When there is the record that satisfies the determination condition inthe read-out record groups (“Yes” in S13-4), as illustrated in FIG. 11,the management server 11 stores a service name and a time zone that areincluded in the record, in the time zone candidate table (S13-5). Atthat time, when the same service name and time zone have been alreadystored in the time zone candidate table, the management server 11 doesnot store the service name and the time zone.

The management server performs increment of the counter variable j(S13-6).

The management server 11 repeats the processing of S13-2 to S13-6 by“T−Y+1” times (S13-7). “T” is a value that is depends on the adoptedunit of aggregation, and for example, when the adopted unit ofaggregation corresponds to “year”, “T=12” is obtained, and when theadopted unit of aggregation corresponds to “month”, “T=28(29), 30, or31” is obtained, and when the adopted unit of aggregation corresponds to“day”, “T=24” is obtained.

FIG. 14 illustrates an example of a flow of the exclusion processing ofthe case where there is no power consumption effect (scheme ofpreventing frequent migration from a viewpoint of power consumption)(S14) in the embodiment. As described above, in S12, there is a casewhere migration in the unit of one hour or a time zone of peak of powerconsumption is determined as a candidate. In the migration in the unitof one hour, when the migration time is considered, intended powerconsumption reduction may not be obtained. In addition, it is desirablethat the migration in the time zone of peak of power consumption isavoided. By considering such a case, “switching unnecessary time (Y05)”and “minimum switching interval (Y06)” are set beforehand, and a timezone that is included in the time range is excluded from the candidateof the time zone in which the migration is performed.

First, the management server 11 sets the number of records in the timezone candidate table 80 to the variable n. In addition, the managementserver 11 initializes the counter variable j by 1 (S14-1).

The management server 11 reads out the j-th record from the time zonecandidate table 80 (S14-2). The management server 11 determines whetheror not “switching unnecessary time (Y05)” is included in “time zone” ofthe read-out j-th record (S14-3).

When “switching unnecessary time (Y05)” is included in “time zone” ofthe read-out j-th record (“Yes” in S14-3), the management server 11deletes the j-th record from the time zone candidate table 80 (S14-4).The management server 11 performs increment of the counter variable j(S14-5).

The management server 11 repeats the processing of S14-2 to S14-5 by “n”times (S14-6).

After that, the management server 11 counts the current number ofrecords in the time zone candidate table 80, and updates a value of “n”by the count number. In addition, the management server 11 initializesthe counter variable j by 1 (S14-7).

The management server 11 reads out the j-th and the j+1-th records fromthe time zone candidate table 80 (S14-8). The management server 11determines whether or not a time interval between the j-th and thej+1-th records is less than “minimum switching interval (Y06)” (S14-9).

When the time interval between the j-th and the j+1-th record is lessthan “minimum switching interval (Y06)” (“Yes” in S14-9), the managementserver 11 deletes the j-th record from the time zone candidate table 80(S14-10). The management server 11 performs increment of the countervariable j (S14-11).

The management server 11 repeats the processing of S14-8 to S14-11 by“n” times (S14-12).

Next, selection processing (S15) of a virtual server to be migrated anda physical server that is a migration destination is described withreference to FIGS. 15A-15C.

FIGS. 15A-15C illustrate an example of a flow of the selectionprocessing (S15) of a virtual server to be migrated and a physicalserver that is a migration destination in the embodiment. The flow ofFIGS. 15A-15C is executed in the unit of business service.

The management server 11 initializes a counter variable m by 0 (S15-1).The management server 11 obtains the operation information 56 of thevirtual server and a list of physical servers which are on (NS[n])through the collection unit 22 (S15-2). Here, “n” corresponds to thenumber of physical servers which are power on. Therefore, a list of allphysical servers which are power on (NS[0] to NS[n−1]) is obtained.

The management server 11 obtains a service that corresponds to a certaintime zone from the time zone candidate table 80. The management server11 obtains the name of a virtual server that performs the service fromthe service management information 50 (S15-3). Here, a physical serveron which the virtual server is operated is represented in NS[m] (S15-4).

The management server 11 calculates an online response time (N3) of theservice that is obtained in S15-3, from the obtained operationinformation 56 of the virtual server using the following formula(S15-5).The online response time N3=(A10)−(A01)

After that, the management server 11 calculates a safety level (N1) ofthe obtained service (S15-6). Here, an online response time (ratio of anonline response time to SLA) is indicated by the following formula.The online response time(ratio of an online response time toSLA)=N3(online response time)/SLA response timeTherefore, the management server 11 calculates a safety level of theservice from the calculated online response time using the safety leveltable 55. For example, “online response time (N3)=7 seconds” and “SLAresponse time=10 seconds” are satisfied, “online response time (ratio ofan online response time to SLA)= 7/10=70%” is obtained. In this case,“safety level of the service=4” is obtained from FIG. 6.

The management server 11 calculates online response times (N5, N6, andN7) of virtual servers that are used for the service using the operationinformation 56 (A01 to A19) of the virtual server, which is obtained bythe collection unit 22 (S15-7). Here, the management server 11calculates processing performance information of each of the virtualservers for one service request (online response time) using thefollowing formula.The processing time N5 of the front server=((A02)−(A01))+((A10)−(A09))The processing time N6 of the APL server=((A04)−(A03))+((A08)−(A07))The processing time N7 of the DB server=((A06)−(A05))

The management server 11 calculates an occupation proportion of aprocessing time of each of the virtual servers in the online responsetime using the following formula (S15-8).The processing time occupation proportion N8 of the front server=N5/N3The processing time occupation proportion N9 of the APL server=N6/N3The processing time occupation proportion N10 of the DB server=N7/N3

The management server 11 uses the following formula to calculate asafety level (N2) for which a response time is considered (S15-9).The safety level (N2) for which a response time is considered=safetylevel×the occupation proportion in the response timeFor example, when “occupation proportion in a response time N8=0.1, and“N9=0.5”, and “N10=0.4” are satisfied in a case where “safety levelN1=2” is satisfied, the safety levels (N2) for which response times ofthe WEB server, the APL server, and the DB server are considered arecalculated as indicated below.N2(WEB)=N1×N8=2×0.1=0.2N2(APL)=N1×N9=2×0.5=1.0N2(DB)=N1×N10=2×0.4=0.8

The management server 11 initializes a counter variable i by 0 (S15-10).The management server 11 determines whether or not the variable m andthe variable are the same value (S15-11). When the variable m and thevariable i are the same value (“Yes” in S13-11), the flow proceeds toprocessing of S15-20.

When the variable m and the variable i are not the same value (“No” inS15-11), the management server 11 executes next processing. That is, themanagement server 11 obtains a ratio (N11) of the number of CPU clocksbetween the physical server NS[m] and the physical server NS[i] that isa comparison target using the physical server management information 30(S15-12).N11=number of CPU clocks(physical server NS[m])/number of CPUclocks(physical server NS[i] that is a comparison target)

After that, the management server 11 obtains a safety level (N4) of theservice when the virtual server is migrated (S15-13). First, themanagement server 11 calculates a safety level (N12) after migration ofthe virtual server that is a migration target using the followingformula.N12=N2×N11For example, when the virtual server to be migrated is the WEB server,“N12(WEB)=N2(WEB)×N11” is calculated. When the virtual server to bemigrated is the APL server, “N12(APL)=N2(APL)×N11” is calculated. Whenthe virtual server to be migrated is the DB server, “N12(DB)=N2(DB)×N11”is calculated.

After that, the management server 11 uses the safety level (N12) aftermigration of the virtual server that is a migration target to calculatea safety level (N4) of the service after migration on the basis of thefollowing formula.The safety level (N4) of the service=the safety level of the Webserver+the safety level of the APL server+the safety level of the DBserver

This flow is processed in the unit of service. Therefore, when allvirtual servers that execute a service that is a current processingtarget operates on the physical server NS[m], all of the virtual serversthat execute the service become migration targets. In this case, thesafety level (N4) of the service after migration is as follows.The safety level (N4) of the service=the safety level (N12) of the WEBserver+the safety level (N12) of the APL server+the safety level (N12)of the DB server.

In addition, it is assumed that apart of the virtual servers thatexecute the service that is the current processing target operates onthe physical server NS[m], and the remaining virtual servers operates onanother physical server. In this case, for the physical server NS[m],only the part of virtual servers are migration targets, and theremaining virtual server are not migration targets. In this case, thesafety level (N12) after migration is used to calculate the safety level(N4) of the service after migration for the virtual server that is themigration target, and the safety level (N4) of the service aftermigration is calculated for the virtual server that is not a migrationtarget using the current safety level (N2). For example, when the WEBserver is only migrated, “N4=N12(WEB)+N2(APL)+N2(DB)” is calculated.When the APL server is only migrated, “N4=N2(WEB)+N12(APL)+N2(DB)” iscalculated. When the DB server is only migrated,“N4=N2(WEB)+N2(APL)+N12(DB)” is calculated. When the WEB server and theAPL server are migrated, “N4=N12(WEB)+N12(APL)+N2(DB)” is calculated.

In addition, when each of the plurality of virtual servers that executethe service that is the current processing target are migrated todifferent physical servers, the same method as the above-describedmethod may be employed. That is, it is assumed that, in each of theplurality of virtual servers, only the virtual server is a migrationtarget (noted virtual server), and the remaining virtual servers are notthe migration targets, and the same calculation method as theabove-described method may be employed for each of the noted virtualservers.

After that, the management server 11 registers information that is usedto determine whether the virtual server that executes the service thatis the current processing target on the physical server NS[m] is enabledto be migrated to the physical server NS[i] that is a comparison target,to the migration availability server list (S15-14). The above-describedprocessing is described below using FIG. 16.

FIG. 16 illustrates an example of a migration availability server listin the embodiment. A migration availability server list 90 is stored inthe storage unit 29. The migration availability server list 90 includesitems of “day”, “service”, “physical server that is a migration source(power-off candidate)”, “VM”, and “physical server that is a migrationdestination”. In addition, the list includes items of “service safetylevel (N4) after migration”, “CPU usage rate (%) of a physical serverthat is a migration destination”, “memory usage rate (%) of a physicalserver that is a migration destination”, “busy rate (%) of a disk of aphysical server that is a migration destination”, and “migrationavailability”.

Here, “day” indicates a day in which a service is performed. Inaddition, “service” indicates a name that is used to identify a service.In addition, “physical server that is a migration source (power-offcandidate)” indicates a physical server that is indicated by thephysical server NS[m], that is, a physical server that is a migrationsource. In addition, “VM” indicates information that is used to identifya virtual server (virtual machine: VM) that operates in the physicalserver. In addition, “physical server that is a migration destination”indicates information that is used to identify a physical server that isindicated by the physical server NS[i] that is a comparison target. In“service safety level (N4) after migration, the service safety level(N4) after migration is stored. In “CPU usage rate (%) of a physicalserver that is a migration destination”, the CPU usage rate (%) of aphysical server that is a migration destination is stored. In “memoryusage rate (%) of a physical server that is a migration destination”, amemory usage rate (%) of a physical server that is a migrationdestination is stored. In “busy rate (%) of a disk of a physical serverthat is a migration destination”, a busy rate (%) of a disk of aphysical server that is a migration destination is stored. In “migrationavailability”, a result that is obtained by determining whether or notthe virtual server of the physical server NS[m] is enabled to bemigrated to the physical server NS[i] that is a comparison target isstored.

In S15-14, the management server 11 registers “day”, “service”,“physical server that is a migration source (power-off candidate)”,“VM”, “physical server that is a migration destination”, and “servicesafety level (N4) after migration”, to the migration availability serverlist 90. In addition, the management server obtains “CPU usage rate”,“memory usage rate”, and “busy rate of a disk” of the physical serverNS[i] that is a comparison target from the physical server managementinformation 30, and registers the information to the migrationavailability server list 90. It is noted that registration of “migrationavailability” is performed in S15-20.

After that, the management server 11 uses the migration availabilityserver list 90 to determine, for example, the physical server NS[i] thatis a comparison target, which satisfies all of the following fourconditions, to be a migration destination physical server candidate(S15-15 to S15-19).

The service safety level (N4) after migration<T1 (S15-15)

The CPU usage rate of the physical server NS[i] that is a comparisontarget<T2% (S15-16)

The memory usage amount of the physical server NS[i] that is acomparison target<T3% (S15-17)

The busy rate of a disk of the physical server NS[i] that is acomparison target<T4% (S15-18)

Here, T1, T2, T3, and T4 are threshold values, certain integers are setto T1, T2, T3, and T4, respectively. For example, to T3, “3” is set. Forexample, to T2 to T4, a usage rate of a resource of the server, forexample, 70 is set.

The management server 11 performs registration of migration availabilityto the migration availability server list 90 (S15-20). The managementserver 11 registers “∘” to “migration availability” of the migrationavailability server list 90 when all of the above-described fourconditions are satisfied, and registers “x” to “migration availability”of the migration availability server list 90 when not all of theabove-described four conditions are satisfied. In the example of FIG.16, it is understood that, for a service A, a virtual server APL-1 of aphysical server NS08 is enabled to be migrated to a physical serverNS04. In addition, it is understood that a virtual server APL-3 of aphysical server NS10 is enabled to be migrated to a physical serverNS03.

After that, the management server 11 determines whether or not thevariable i is smaller than the number of physical servers n the power ofwhich is turned on (S15-21). When the variable i is smaller than thenumber of physical servers n the power of which is turned on (“Yes” inS15-21), the management server 11 performs increment of the variable i(S15-22), and the flow returns to the processing of S15-11. When thevariable i is equal to or larger than the number of physical servers nthe power of which is turned on (“No” in S15-21), the management server11 determines whether or not the variable m is smaller than the numberof physical servers n the power of which is turned on (S15-23).

When the variable m is smaller than the number of physical servers n thepower of which is turned on (“Yes” in S15-23), the management server 11performs increment of the variable m (S15-24), and the flow returns tothe processing of S15-3. When the variable m is equal to or larger thanthe number of physical servers n the power of which is turned on (“No”in S15-23), the flow ends.

FIG. 17 illustrates an example of a flow of exclusion processing of thecase where there is no power consumption effect (availabilityverification of a physical server candidate that is a migrationdestination) in the embodiment (S16). The management server 11initializes the counter variable by 0 (S16-1).

The management server 11 extracts incident information that correspondsto a physical server [i] in “occurrence source” and “system termination”in an incident category, from an incident management table 100illustrated in FIGS. 18A and 18B (S16-2).

The management server 11 calculates MTBF (meantime between failures)using the extracted incident information (S16-3). The calculation of theMTBF is described with reference to FIGS. 18A and 18B.

FIGS. 18A and 18B illustrate an example of an incident management tablein the embodiment. The incident management table 100 is a table that isused to manage an occurred incident as incident information, and isstored in the storage unit 29. The incident management table 100includes “incident number”, “segment”, “category 1”, “occurrencesource”, “occurrence day”, “MTBF”, “request source”, . . . , “content”,and “solution day”.

Here, “incident number” is a number that is used to identify incidentinformation. In addition, “segment” is an item that is used todistinguish “failure”, “Q&A”, “work request”, and the like. In addition,“category 1” indicates a category such as “system termination”,“operation procedure”, and the like. In addition, “occurrence source”indicates an occurrence source of the incident. In addition, “occurrenceday” indicates an occurrence day of the incident. In addition, “MTBF”indicates an interval after an incident of the system has previouslyoccurred. In addition, “content” indicates a content of the incident. Inaddition, “solution day” indicated a day in which the incident issolved.

The management server 11 extracts incident information of “systemtermination” in a unit of “occurrence source” from the incidentmanagement table 100. For example, when the occurrence source is “serverA”, pieces of incident information of occurrence days “2011/1/23”,“2011/3/15”, “2011/5/15”, “2011/7/31”, and “2011/9/20” are extracted.Intervals of occurrence days of the extracted incident information are51 days, 61 days, 77 days, and 51 days, so that “MTBF=(51+61+77+51)/4=60days” is obtained. The time period of 60 days is a time period duringwhich a probability that a failure occurs after a day in which a systemfailure has previously occurred is low.

After that, the management server 11 creates a migration enable timeperiod calendar using calendar information, a day in which a systemfailure has previously occurred, a safety time period even when thesystem terminates, the calculated MTBF (S16-4). The migration enabletime period calendar is described with reference to FIG. 19.

FIG. 19 illustrates an example of the migration enable time periodcalendar in the embodiment. A migration enable time period calendar 110corresponds to information that is used to manage an occurrence day ofthe incident and a migration enable time period on the calendar for eachof the physical servers. The management server 11 adds the safety timeperiod even the system (physical server [i]) terminates to the day inwhich a system failure has previously occurred, and as illustrated inFIG. 19, the addition is reflected to the migration enable time periodcalendar. Here, the last day of the safety time period even when thesystem (physical server [i]) terminates is obtained by the followingformula.The last day of the safety time period even when the systemterminates=the day in which a system failure has previouslyoccurred+(MTBF−10 days)−1 day=2011/9/20+(60−10)−1=2011/11/8Therefore, during 2011/9/20 to 2011/11/9, it is determined that aprobability that a termination failure of the physical server [i] doesnot occur is high. As illustrated in FIG. 19, the management server 11reflects a time period from an incident occurrence day of the latestserver termination to the MTBF (safety index is obtained by minus 10days) in the migration enable time period calendar as “migration safetytime period”.

After that, the management server 11 performs matching between a day ofthe migration enable time period calendar 110 and a day of a record ofthe physical server [i] in which “∘” is set to “migration availability”in the migration availability server list 90. The management server 11creates a server operation schedule calendar on the basis of the matchedday (S16-5). The server operation schedule calendar is used to determineactual operation/termination of a physical server. The server operationschedule calendar is described with reference to FIG. 20.

FIG. 20 illustrates an example of the server operation schedule calendarin the embodiment. A server operation schedule calendar 120 is acalendar in which a migration enable flag “1” is set to a day thatcorresponds to the day of the record of the physical server [i] in which“∘” is set to “migration availability” of the migration availabilityserver list 90, in the migration enable time period calendar 110. Here,“migration enable time period” of the server operation schedule calendar120 indicates a time period during which it is determined that aprobability that termination failure of the physical server [i] does notoccur is high.

Using the server operation schedule calendar 120, it can be determinedthat a time period during which “migration enable time period” and themigration enable flag “1” are overlapped with each other is a timeperiod during which a virtual server can be actually migrated and thepower of a physical server that is a migration source can be turned off.

After the processing in S16-5, the management server 11 performsincrement of the counter variable i (S16-6). For all of the physicalservers, the processing of S16-2 to S16-6 is repeated (S16-7).

After that, migration of a virtual server and power-off of a physicalserver are described using FIGS. 21 and 22.

FIGS. 21A and 21B illustrate an example of a flow of the migration of avirtual server and the power-off processing a physical server (S17) inthe embodiment. The management server 11 obtains a list of all of thephysical servers which are on (NS[n]) (S17-1). Here, “n=the number ofall physical servers the power of which is turned on” is satisfied.Therefore, a list that includes NS[1] to NS[n] as elements is obtained.

The management server 11 initializes the counter variable i by 0(S17-2). The management server 11 performs increment of the countervariable i (S17-3). The management server 11 obtains a list of allvirtual servers that operate on the physical server NS[i] (NVM[m])(S17-4). Here, “m=the number of all virtual servers that operate on thephysical server NS[i]” is satisfied. Therefore, a list that includes theNVM[1] to NVM[m] that operate on the physical server NS[i] as elementsis obtained.

The management server 11 obtains a schedule of the physical server NS[i]to which a migration enable flag is set, from the server operationschedule calendar 120 (S17-5). The management server 11 obtains a recordof the physical server NS[i] in a day that corresponds to the obtainedschedule, from the migration availability server list 90 (S17-6).

The management server 11 uses the record that is obtained in S17-6 todetermine whether or not all of the virtual servers (NVM[1] to NVM[m])that operate on the physical server NS[i] can be migrated to anotherphysical server (S17-7). The processing of S17-7 is described withreference to FIG. 22. When not all of the virtual servers (NVM[1] toNVM[m]) that operate on the physical server NS[i] can be migrated toanother physical server (“No” in S17-7), the flow proceeds to processingof S17-10.

When all of the virtual servers (NVM[1] to NVM[m]) that operate on thephysical server NS[i] can be migrated to another physical server (“Yes”in S17-7), the management server 11 executes next processing. That is,the management server 11 determines whether or not the physical serverNS[i] is not a migration destination candidate using the record that isobtained in S17-6 (S17-8). The processing of S17-8 is described withreference to FIG. 22. When the physical server NS[i] is a migrationdestination candidate (“No” in S17-8), the flow proceeds to processingof S17-10.

Using the migration availability server list 90, when the physicalserver NS[i] is not a migration destination candidate (“Yes” in S17-8),the management server 11 determines the physical server NS[i] to be acandidate of a physical server the power of which is turned off. Themanagement server 11 stores information on the physical server NS[i]that is determined to be the candidate of a physical server the power ofwhich is turned off in the migration/power-OFF candidate table (S17-9).

The processing of S17-3 to S17-9 is repeated by the number of elements nthat are included in the list of all of the physical servers which areon (NS[n]) (S17-10).

FIG. 22 is a diagram illustrating the processing of S17-7 to S17-9. FIG.23 illustrates an example of a migration/power-OFF candidate table inthe embodiment. A list in FIG. 22 is the migration availability serverlist 90. For example, in December 1st, all of VMs in the physical serverNS08 can be migrated to another physical server, and the physical serverNS08 is not a candidate of a migration destination of the VMs. In thiscase, the management server 11 extracts information on the physicalserver NS08 from the migration availability server list 90, and storesthe information in a migration/power-OFF candidate table 130. In themigration/power-OFF candidate table 130, “day”, “service”, “physicalserver power-off candidate before migration”, “VM”, “migrationdestination” of the migration availability server list 90 are stored.

In a physical server NS09, virtual servers “APL-2” and “DB-1” cannot bemigrated, that is, not all the virtual servers can be migrated, so thatthe power cannot be turned OFF.

The physical server NS09 is a migration destination of the virtualserver APL-1 of the physical server NS08, so that the power cannot beturned OFF.

Returning to FIGS. 21A and 21B, the management server 11 executes nextprocessing before the migration enable time. That is, the managementserver 11 obtains the name of a virtual server that is a migrationtarget, the name of a physical server on which the virtual server isoperated, and the name of a physical server that is a migrationdestination candidate, from the migration/power-OFF candidate table 130.Using the obtained information, the management server obtains a virtualserver from the physical server that is a migration source and buildsthe virtual server on a physical server that is a migration destinationby server migration (S17-11).

The management server 11 switches the physical server on which thevirtual server that is a migration target is operated, from a migrationsource physical server to a migration destination physical server, atthe migration enable time (S17-12). After that, the management server 11issues a command that indicates that the power of the physical serverthat is a migration source is turned off, to the physical server that isa migration source (S17-13). The physical server that is a migrationsource turns off the power when the physical server receives thecommand.

Next, output processing of a power consumption reduction amount aftermigration (S18) is described with reference to FIG. 24. The managementserver 11 calculates operational consumption power of the service bycombining operational consumption power of all physical servers on whichthe systems used for the service are operated.

FIG. 24 illustrates an output example of a power consumption reductionamount after migration in the embodiment. The output content of thepower consumption reduction amount after migration includes data itemsof “migration target service name”, “migration target time zone”,“migration source physical server name”, “virtual server name”, and“migration destination physical server”. In addition, the output contentincludes data items of “operational consumption power (W) beforemigration”, “operational consumption power (W) after migration”, and“reduction power (W) (operational consumption power beforemigration-operational consumption power after migration)”.

Here, “migration target service name” indicates the name of a servicethat is a migration target. In addition, “migration target time zone”indicates a time zone of a migration target. In addition, “migrationsource physical server name” indicates the name of a physical serverthat is a migration source of a virtual server that executes theservice. In addition, “virtual server name” indicates the name of avirtual server that executes the service in the migration sourcephysical server. In addition, “migration destination physical servername” indicates the name of physical server that is a migrationdestination of the virtual server. In addition, “operational consumptionpower (W) before migration” indicates operational consumption power (W)before migration of a virtual server of the service. In addition,“operational consumption power (W) after migration” indicatesoperational consumption power (W) after migration of the virtual server.In “reduction power (W) (operational consumption power beforemigration−operational consumption power after migration)”, a value of“operational consumption power (W) before migration−operationalconsumption power (W) after migration” is stored.

In the embodiment, an operation of the information processing devicehaving excellent energy efficiency such as reduction in the usage powerof the information processing device can be realized while a servicelevel of the business service is kept. In addition, the power of an airconditioner that is used to cool heat due to the information processingdevice can be reduced. In addition, a power consumption reduction amountthat is reduced by migration can be checked.

FIG. 25 is a configuration block diagram illustrating a hardwareenvironment of a computer to which the embodiment is applied. A computer150 functions as the management server 11 by reading a program thatexecutes the processing in the embodiment.

The computer 150 includes an output I/F 151, a CPU 152, a ROM 153, acommunication I/F 154, an input I/F 155, a RAM 156, a storage device157, a reading device 158, and a bus 159. The computer 150 can beconnected to an output device 161, and an input device 162.

Here, the CPU indicates a central processing unit. The ROM indicates aread-only memory. The RAM indicates a random access memory. The I/Findicates an interface. To the bus 159, the output I/F 151, the CPU 152,the ROM 153, the communication I/F 154, the input I/F 155, the RAM 156,the storage device 157, and the reading device 158 are connected. Thereading device 158 is a device that performs reading from a portablerecording medium. The output device 161 is connected to the output I/F151. The input device 162 is connected to the input I/F 155.

As the storage device 157, a storage device having various formats suchas a hard disk drive device, a flush memory device, and a magnetic diskdevice can be used.

In the storage device 157 or the ROM 153, for example, the program thatachieves the processing that is described in the embodiment is stored.In addition, in the storage device 157 or the ROM 153, the physicalserver management information 30, the virtual server managementinformation 40, the service management information 50, the safety leveltable 55, and the operation information 56 of a virtual server arestored. In addition, in the storage device 157 or the ROM 153, theappearance rate information (Y00-1) analysis table 60, the appearancerate information (Y00-2) analysis table 70, the time zone candidatetable 80, the migration availability server list 90, and the incidentmanagement table 100 are stored. In addition, in the storage device 157or the ROM 153, the migration enable time period calendar 110, theserver operation schedule calendar 120, and the migration/power-offcandidate table 130 are stored.

The CPU 152 reads the program that achieves the processing that isdescribed in the embodiment and is stored in the storage device 157, andexecutes the program. Specifically, the CPU 152 functions as the controlunit 4 (the obtaining unit 21, the collection unit 22, the serviceidentification unit 23, the candidate determination unit 24, theexception processing unit 25, the VM migration control unit 26, thepower-off control unit 27, and the output unit 28) by executing theprogram.

The program that achieves the processing that is described in theembodiment may be stored for example, in the storage device 157 througha communication network 160 and the communication I/F 154 from the aprogram provider side. In addition, the program that achieves theprocessing that is described in the embodiment may be stored in aportable storage medium that is commercially available and put intocirculation. In this case, the portable storage medium is installed inthe reading device 158, and the program may be readout and executed bythe CPU 152. As the portable storage medium, a storage medium havingvarious formats such as a CD-ROM, a flexible disk, an optical disk, amagneto-optical disk, an integrated circuit (IC) card, and a universalserial bus (USB) memory device can be used. The program that is storedin such a storage medium is read by the reading device 158.

In addition, as the input device 162, a keyboard, a mouse, an electroniccamera, a web camera, a microphone, a scanner, a sensor, a tablet, atouch panel, and the like can be used. In addition, as the output device161, a display, a printer, a speaker, and the like can be used. Inaddition, as the communication network 160, the Internet, a LAN, a WAN,a dedicated line, a wired line, a wireless line, and the like may beused.

It is noted that the present invention can be not intended to be limitedto the embodiments described above, and various configurations orembodiments can be employed without departing from the scope of thepresent invention.

According to an aspect of the present invention, a technology can beprovided by which power consumption of the information processing systemis reduced while a service level is taken into consideration.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a depicting of the superiorityand inferiority of the invention. Although the embodiments of thepresent invention have been described in detail, it should be understoodthat the various changes, substitutions, and alterations could be madehereto without departing from the spirit and scope of the invention.

What is claimed is:
 1. An apparatus for controlling an informationprocessing system, the apparatus comprising: a memory; and a controlunit configured to perform a process including: obtaining responseinformation that includes a result of processing executed by a pluralityof virtual machines that operates on a first information processingdevice, in response to request information that is transmitted to theinformation processing system that includes a plurality of informationprocessing devices, the first information processing device beingincluded in the plurality of information processing devices; calculatinga first evaluation value that is used to evaluate a response time fromtransmission of the request information to reception of the responseinformation; calculating a value that depends on a ratio of a processingcapability of the first information processing device to a processingcapability of a second information processing device, the secondinformation processing device being included in the plurality ofinformation processing devices and reserving capacity for executing theprocessing; calculating an occupation proportion of a processing time ofeach of the plurality of virtual machines in the response time, theprocessing time being a time taken by each of the plurality of virtualmachines to execute the processing; calculating, based on the firstevaluation value, the value that depends on the ratio and the occupationproportion, a second evaluation value that is used to evaluate aprocessing time that occurs when the virtual machines operates on thesecond information processing device, the processing time being a periodof time extending from transmission of the request information toreception of the response information; determining the secondinformation processing device to be a migration destination candidate ofthe virtual machines when the calculated second evaluation value issmaller than a first threshold value; and migrating the virtual machinesthat operates on the first information processing device to themigration destination candidate to turn off power of the firstinformation processing device.
 2. The apparatus according to claim 1,wherein in the determining, the second information processing device isdetermined to be the migration destination candidate of the virtualmachines when a value of a usage rate of a resource of the secondinformation processing device is smaller than a second threshold value.3. The apparatus according to claim 1, wherein in the migrating of thevirtual machines in the migration destination candidate, when aplurality of virtual machines operate on the first informationprocessing device, and the response information is processed by all or apart of the plurality of the virtual machines, the migration destinationcandidate is determined for each of the plurality of informationprocessing devices, and all or a part of the virtual machines that haveprocessed the response information is migrated to the migrationdestination candidate when the first information processing device isnot determined to be the migration destination candidate.
 4. Theapparatus according to claim 1, wherein in the migrating of the virtualmachines in the migration destination candidate, mean time betweenfailures is calculated using failure history information of the secondinformation processing device, a most recent failure occurrence day isobtained from the failure history information, a next failure occurrencepredicted day is calculated from the failure occurrence day and the meantime between failures, the virtual machine that operates on the firstinformation processing device is migrated to the migration destinationcandidate in a day within a period from the most recent failureoccurrence day to the next failure occurrence predicted day, and powerof the first information processing device is turned off.
 5. Theapparatus according to claim 1, the process further including:calculating an evaluation value that is used to evaluate processingperformance from transmission of the request information to reception ofthe response information, calculating an appearance rate of theevaluation value for each of the evaluation values in a first unit oftime, and identifying a first time zone in which the appearance rateexceeds a threshold value in any of the evaluation values.
 6. Theapparatus according to claim 5, wherein in the identifying of the firsttime zone, an appearance rate of the evaluation value is calculated in asecond unit of time, which is a lower-level of the first unit of timefor each of the evaluation values, and a second time zone in which theappearance rate exceeds a threshold value in any of the evaluationvalues identified out of consecutive time zones in the second unit oftime.
 7. The apparatus according to claim 6, wherein in the identifyingof the first time zone, the identified first time zone is excluded whena certain day or a time zone is included in the identified first timezone, and the identified second time zone is excluded when a length ofthe identified second time zone is shorter than a threshold value.
 8. Anon-transitory computer-readable recording medium having stored thereina program for causing a computer to execute process for controlling aninformation processing system, the process comprising: obtainingresponse information that include a result of processing executed by aplurality of virtual machines that operates on a first informationprocessing device, in response to request information that istransmitted to the information processing system that includes aplurality of information processing devices, the first informationprocessing device being included in the plurality of informationprocessing devices; calculating a first evaluation value that is used toevaluate a response time from transmission of the request information toreception of the response information, calculating a value that dependson a ratio of a processing capability of the first informationprocessing device to a processing capability of a second informationprocessing device, the second information processing device beingincluded in the plurality of information processing devices andreserving capacity for executing the processing; calculating anoccupation proportion of a processing time of each of the plurality ofvirtual machines in the response time, the processing time being a timetaken by each of the plurality of virtual machines to execute theprocessing; calculating, based on the first evaluation value, the valuethat depends on the ratio and the occupation proportion, a secondevaluation value that is used to evaluate a response time that occurswhen the virtual machines operates on the second information processingdevice, the processing time being a period of time extending fromtransmission of the request information to reception of the responseinformation, determining the second information processing device to bea migration destination candidate of the virtual machines when thecalculated second evaluation value is smaller than a first thresholdvalue; and migrating the virtual machines that operates on the firstinformation processing device to the migration destination candidate toturn off power of the first information processing device.
 9. Thenon-transitory computer-readable recording medium according to claim 8,wherein in the determining, the second information processing device isdetermined to be the migration destination candidate of the virtualmachines when a value of a usage rate of a resource of the secondinformation processing device is smaller than a second threshold value.10. The non-transitory computer-readable recording medium according toclaim 8, wherein in the migrating of the virtual machines in themigration destination candidate, when a plurality of virtual machinesoperate on the first information processing device, and the responseinformation is processed by all or a part of the plurality of thevirtual machines, the migration destination candidate is determined foreach of the plurality of information processing devices, and all or apart of the virtual machines that have processed the responseinformation are migrated to the migration destination candidate when thefirst information processing device is not determined to be themigration destination candidate.
 11. The non-transitorycomputer-readable recording medium according to claim 8, wherein in themigrating of the virtual machines in the migration destinationcandidate, mean time between failures is calculated using failurehistory information of the second information processing device, a mostrecent failure occurrence day is obtained from the failure historyinformation, a next failure occurrence predicted day are calculated fromthe failure occurrence day and the mean time between failures, thevirtual machine that operates on the first information processing deviceis migrated to the migration destination candidate in a day within aperiod from the most recent failure occurrence day to the next failureoccurrence predicted day, and power of the first information processingdevice is turned off.
 12. The non-transitory computer-readable recordingmedium according to claim 8, the processing further including:calculating an evaluation value that is used to evaluate processingperformance from transmission of the request information to reception ofthe response information, calculating an appearance rate of theevaluation value for each of the evaluation values in a first unit oftime, and identifying a first time zone in which the appearance rateexceeds a threshold value in any of the evaluation values.
 13. Thenon-transitory computer-readable recording medium according to claim 12,wherein in the identifying of the first time zone, an appearance rate ofthe evaluation value is calculated in a second unit of time, which is alower-level of the first unit of time for each of the evaluation values,and a second time zone in which the appearance rate exceeds a thresholdvalue in any of the evaluation values is identified out of consecutivetime zones in the second unit of time.
 14. The non-transitorycomputer-readable recording medium according to claim 12, wherein in theidentifying of the first time zone, further, the identified first timezone is excluded when a certain day or time zone is included in theidentified first time zone, and the identified second time zone isexcluded when a length of the identified second time zone is shorterthan a threshold value.
 15. A method for controlling an informationprocessing system, the method comprising: obtaining, by using acomputer, response information that include a result of processingexecuted by a plurality of virtual machine machines that operates on afirst information processing device, in response to request informationthat is transmitted to the information processing system that includes aplurality of information processing devices, the first informationprocessing device being included in the plurality of informationprocessing devices; calculating, by using the computer, a firstevaluation value that is used to evaluate a response time fromtransmission of the request information to reception of the responseinformation; calculating, by using the computer, a value that depends ona ratio of a processing capability of the first information processingdevice to a processing capability of a second information processingdevice, the second information processing device being included in theplurality of information processing devices and reserving capacity forexecuting the processing; calculating, by using the computer, anoccupation proportion of a processing time of each of the plurality ofvirtual machines in the response time, the processing time being a timetaken by each of the plurality of virtual machines to execute theprocessing; calculating, by using the computer, a second evaluationvalue that is used to evaluate a response time that occurs when thevirtual machines operates on the second information processing device,the processing time being a period of time extending from transmissionof the request information to reception of the response informationbased on the first evaluation value, the value that depends on the ratioand the occupation proportion; determining, by using the computer, thesecond information processing device to be a migration destinationcandidate of the virtual machines when the calculated second evaluationvalue is smaller than a first threshold value; and migrating, by usingthe computer, the virtual machines that operates on the firstinformation processing device to the migration destination candidate toturn off power of the first information processing device.